By comparison, referenced in my other comments, if someone really wanted to kill everyone in a theater they could do it with a container of gasoline, or a pressure cooker. Newtown could have been accomplished with a sword, given the size difference of the attacker to the victims.
Anyone who wants to kill you can, with any number of objects readily accessible. This is only evident to some people when they think of an object like an AR-15 because they don't think about all the other ways they could be killed.